Comparison between exhaled breath condensate analysis as a marker for cobalt and tungsten exposure and biomonitoring in workers of a hard metal alloy processing plant

Outlining Potential Biomarkers of Exposure and Effect to Critical Minerals: Nutritionally Essential Trace Elements and the Rare Earth Elements

Emerging and low-carbon technologies and innovations are driving a need for domestic sources, sustainable use, and availability of critical minerals (CMs)-those vital to the national and economic security of the United States. Understanding the known and potential health effects of exposures to such mineral commodities can inform prudent and environmentally responsible handling and harvesting. We review the occurrence, use, predominant exposure pathways, and adverse outcome pathways (AOP) for human and fish receptors of those CMs that are nutritionally essential trace metals (specifically, cobalt, chromium, manganese, nickel, and zinc), as well as the rare earth elements. Biological responses to some elements having comparable biogeochemistry can sometimes be similar. Candidate quantifiable biomarkers for assessing potential AOP are conveyed.

HBM4EU chromates study - the measurement of hexavalent and trivalent chromium in exhaled breath condensate samples from occupationally exposed workers across Europe

The aim of this study was to investigate the practicability of exhaled breath condensate (EBC) as a biological matrix to detect and measure hexavalent chromium (Cr(VI)) and trivalent chromium (Cr(III)) in workers occupationally exposed to Cr(VI). EBC samples were collected from workers in France, Finland, Italy, The Netherlands and the United Kingdom from three different target activities: chrome platers, stainless steel welders and surface treatment workers. Pre and post working week EBC samples were collected from 177 exposed workers and 98 unexposed workers (control group). Hyphenated chromatography systems with inductively coupled plasma - mass spectrometry (ICP-MS) were for the analysis. The results showed that the occupationally exposed workers had significantly higher levels of Cr(VI) and Cr(III) than the control group. Chrome platers exhibited the highest Cr(VI) levels in their EBC samples, with a significant increase from their pre to post samples for both Cr(VI) and Cr(III). A significant difference was also found between pre and post EBC samples for Cr(III) in welders. This study has shown that EBC has the potential to be a valid, non-invasive biological matrix to assess occupational exposure to Cr(VI) and Cr(III) for biological monitoring assessment, with the ability to detect low level inhalation exposures.

Occupational low-level exposure to hard metals: cobalt and tungsten biomonitoring as an effective tool to evaluate the effectiveness of industrial hygiene interventions for risk management

Purpose: The aim of the study was to assess the exposure to Cobalt (Co) and Tungsten (W) in a group of hard metal tool sharpeners through a combined approach of air and biological monitoring, and to evaluate the effectiveness of a control and improvement intervention carried out in collaboration with the medical officers of the local Health Protection Agency, by biomonitoring.Methods: We enrolled 132 workers from 17 companies of the province of Brescia, northern Italy. The study was performed in two phases: (1) an environmental and biomonitoring survey to assess the workers' exposure to Co and W at their usual working conditions; (2) a further biomonitoring survey 3 months after the enforcement of a control and improvement intervention, to assess its effectiveness.Results: Workers were found to be exposed to low concentration of airborne dust containing Co and W but after the intervention we recorded a significant decrease of the urinary concentrations of both Co and W. The extent of the decrease was correlated to the number of preventive industrial hygiene interventions that were carried out.Conclusions: Biological monitoring of Co and W in the hard metal tools manufacturing industry is a sensitive and effective method to evaluate the effectiveness of prevention practices.

Transition and post-transition metals in exhaled breath condensate

Water vapor in expired air, as well as dispersed non-volatile components, condense onto a cooler surface after exiting the respiratory tract. This exhaled breath condensate (EBC) provides a dilute sampling of the epithelial lining fluid. Accordingly, the collection of EBC imparts a capacity to provide biomarkers of injury preceding clinical disease. Concentrations of transition and post-transition metals in EBC are included among these endpoints. Iron and zinc are the metals with the highest concentration and are measurable in all EBC samples from healthy subjects; other metals are most frequently either at or below the level of detection in this group. Gender, age, and smoking can impact EBC metal concentrations in healthy subjects. EBC metal concentrations among patients diagnosed with particular lung diseases (e.g. asthma, chronic obstructive disease, and interstitial lung disease) have been of research interest but no definite pattern of involvement has been delineated. Studies of occupationally exposed workers confirm significant exposure to specific metals, but such EBC metal measurements frequently provide evidence redundant with environmental sampling. Measurements of metal concentrations in EBC remain a research tool into metal homeostasis in the respiratory tract and participation of metals in disease pathogenesis. The quantification of metal concentrations in EBC is currently not reliable for clinical use in either supporting or determining any diagnosis. Issues that must be addressed prior to the use of EBC metal measurements include the establishment of both standardized collection and measurement techniques.

Cobalt toxicity in humans-A review of the potential sources and systemic health effects

Cobalt (Co) and its compounds are widely distributed in nature and are part of numerous anthropogenic activities. Although cobalt has a biologically necessary role as metal constituent of vitamin B₁₂, excessive exposure has been shown to induce various adverse health effects. This review provides an extended overview of the possible Co sources and related intake routes, the detection and quantification methods for Co intake and the interpretation thereof, and the reported health effects. The Co sources were allocated to four exposure settings: occupational, environmental, dietary and medical exposure. Oral intake of Co supplements and internal exposure through metal-on-metal (MoM) hip implants deliver the highest systemic Co concentrations. The systemic health effects are characterized by a complex clinical syndrome, mainly including neurological (e.g. hearing and visual impairment), cardiovascular and endocrine deficits. Recently, a biokinetic model has been proposed to characterize the dose-response relationship and effects of chronic exposure. According to the model, health effects are unlikely to occur at blood Co concentrations under 300μg/l (100μg/l respecting a safety factor of 3) in healthy individuals, hematological and endocrine dysfunctions are the primary health endpoints, and chronic exposure to acceptable doses is not expected to pose considerable health hazards. However, toxic reactions at lower doses have been described in several cases of malfunctioning MoM hip implants, which may be explained by certain underlying pathologies that increase the individual susceptibility for Co-induced systemic toxicity. This may be associated with a decrease in Co bound to serum proteins and an increase in free ionic Co²⁺. As the latter is believed to be the primary toxic form, monitoring of the free fraction of Co²⁺ might be advisable for future risk assessment. Furthermore, future research should focus on longitudinal studies in the clinical setting of MoM hip implant patients to further elucidate the dose-response discrepancies.

The simultaneous detection of trivalent & hexavalent chromium in exhaled breath condensate: A feasibility study comparing workers and controls

The analytical method outlined in this feasibility study has been used to show that trivalent chromium (Cr(III)) and hexavalent chromium (Cr(VI)) can be detected and measured in exhaled breath condensate (EBC) samples. EBC samples and urine samples were collected from a cohort of 58 workers occupationally exposed to hexavalent chromium compounds and 22 unexposed volunteers (control group). Levels of Cr(III) and Cr(VI) were determined in EBC samples and total chromium levels were determined in urine samples. Pre and post working week samples for both EBC and urine were collected in tandem. Total chromium in urine samples was analysed by inductively coupled plasma mass spectrometry (ICP-MS). Analysis of Cr(III) and Cr(VI) in EBC samples used a hyphenated micro liquid chromatography (μLC) system coupled to an ICP-MS. Separation was achieved using an anion exchange micro-sized column. The results showed that the occupationally exposed workers had significantly higher levels of Cr(III) and Cr(VI) in their EBC samples than the control group, as well as higher levels of total chromium in their urine samples. However, for the exposed workers no significant difference was found between pre and post working week EBC samples for either Cr(III) or Cr(VI). This study has established that Cr(III) and Cr(VI) can simultaneously be detected and measured in 'real' EBC samples and will help in understanding inhalation exposure.

Assessment of nanoparticles and metal exposure of airport workers using exhaled breath condensate

Aircraft engine exhaust increases the number concentration of nanoparticles (NP) in the surrounding environment. Health concerns related to NP raise the question of the exposure and health monitoring of airport workers. No biological monitoring study on this profession has been reported to date. The aim was to evaluate the NP and metal exposure of airport workers using exhaled breath condensate (EBC) as a non-invasive biological matrix representative of the respiratory tract. EBC was collected from 458 French airport workers working either on the apron or in the offices. NP exposure was characterized using particle number concentration (PNC) and size distribution. EBC particles were analyzed using dynamic light scattering (DLS) and scanning electron microscopy coupled to x-ray spectroscopy (SEM-EDS). Multi-elemental analysis was performed for aluminum (Al), cadmium (Cd) and chromium (Cr) EBC contents. Apron workers were exposed to higher PNC than administrative workers (p  <  0.001). Workers were exposed to very low particle sizes, the apron group being exposed to even smaller NP than the administrative group (p  <  0.001). The particulate content of EBC was brought out by DLS and confirmed with SEM-EDS, although no difference was found between the two study groups. Cd concentrations were higher in the apron workers (p  <  0.001), but still remained very low and close to the detection limit. Our study reported the particulate and metal content of airport workers airways. EBC is a potential useful tool for the non-invasive monitoring of workers exposed to NP and metals.

The suitability of EBC-Pb as a new biomarker to assess occupational exposure to lead

Occupational exposure to lead (Pb) requires continuous surveillance to assure, as much as possible, safe and healthful working conditions. This study addresses the suitability of assessing Pb exposure in relevant workers using their exhaled breath condensate (EBC). This study enrolled workers of two different Pb processing industries characterized by moderate and high Pb exposure levels in the work environment, and a group of non-exposed individuals working in offices who served as baseline for Pb exposure. The EBC-Pb of workers reflected the Pb levels in the work environment of all three settings, although the relationship with B-Pb was not clear. The lack of correlation between EBC-Pb and B-Pb most probably indicates the time lag for Pb to enter in the two body pools. The EBC-Pb seems to reflect immediate exposure, providing a prompt signature of Pb in the environmental that may interact directly with the organ. By delivering short-term evaluation of exposure, EBC-Pb represents a clear advantage in biomonitoring and may become an interesting tool for estimating organ burden.

Characterization of a portable method for the collection of exhaled breath condensate and subsequent analysis of metal content

Using exhaled breath condensate (EBC) as a biological media for analysis of biomarkers of exposure may facilitate the understanding of inhalation exposures. In this study, we present method validation for the collection of EBC and analysis of metals in EBC. The collection method was designed for use in a small scale longitudinal study with the goal of improving reproducibility while maintaining economic feasibility. We incorporated the use of an Rtube with additional components as an assembly, and trained subjects to breathe into the apparatus. EBC was collected from 8 healthy adult subjects with no known elevated exposures to Mn, Cr, Ni, and Cd repeatedly (10 times) within 7 days and analyzed for these metals via ICP-MS. Method detection limits were obtained by mimicking the process of EBC collection with ultrapure water, and resulted in 46-62% of samples falling in a range less than the method detection limit. EBC metal concentrations were found to be statistically significantly associated (p < 0.05) with room temperature and relative humidity during collection, as well as with the gender of the subject. The geometric mean EBC metal concentrations in our unexposed subjects were 0.57 μg Mn per L, 0.25 μg Cr per L, 0.87 μg Ni per L, and 0.14 μg Cd per L. The overall standard deviation was greater than the mean estimate, and the major source in EBC metals concentrations was due to fluctuations in subjects' measurements over time rather than to the differences between separate subjects. These results suggest that measurement and control of EBC collection and analytical parameters are critical to the interpretation of EBC metals measurements. In particular, rigorous estimation of method detection limits of metals in EBC provides a more thorough evaluation of accuracy.

Biomarkers of exposure to metal dust in exhaled breath condensate: methodology optimization

In occupational assessments where workers are exposed to metal dust, the liquid condensate of exhaled breath (EBC) may provide unique indication of pulmonary exposure. The main goal of this study was to demonstrate the quality of EBC to biological monitoring of human exposure. A pilot study was performed in a group of metal dust-exposed workers and a group of nonexposed individuals working in offices. Only metal dust-exposed workers were followed along the working week to determine the best time of collection. Metal analyses were performed with inductively coupled plasma mass spectrometry (ICP-MS). Analytical methodology was tested using an EBC sample pool for several occupationally exposed metals: potassium, chromium, manganese, copper, zinc, strontium, cadmium, antimony, and lead. Metal contents in EBC of exposed workers were higher than controls at the beginning of the shift and remained augmented throughout the working week. The results obtained support the establishment of EBC as an indicator of pulmonary exposure to metals.

Neurotoxicity of cobalt

Cobalt exerts well-known and documented toxic effects on the thyroid, heart and the haematopoietic system, in addition to the occupational lung disease, allergic manifestations and a probably carcinogenic action. Cobalt neurotoxicity is reported in isolated cases, and it has never been systematically treated. Bilateral optic atrophy and retinopathy, bilateral nerve deafness and sensory-motor polyneuropathy have been described long ago as a result of chronic occupational exposure to cobal powder or during long-term treatment of anaemia with cobalt chloride. Recently, some patients with high levels of cobalt released from metal prosthesis have been referred as presenting with tinnitus, deafness, vertigo, visual changes, optic atrophy, tremor and peripheral neuropathy. The aim of this work is to group these cases and to identify a possible mechanism of cobalt neurotoxicity, focusing on hypothetic individual susceptibility such as altered metal-binding proteins, altered transport processes in target cells or polymorphic variation of genetic background.

Contact allergy and human biomonitoring--an overview with a focus on metals

Humans are widely exposed to chemicals. Today, there is an increased acknowledgement of the importance of measuring human and environmental exposures to man-made or refined chemicals. Different approaches have been applied over time, but during the past 25 years, there has been a general trend towards the use of human biomonitoring. A few studies have used human biomonitoring methodology to track contact allergens together with information on patch test reactivity. Hypothetically, the internal load of reactive chemicals might modify the immune response to haptens and the propensity to sensitize and elicit allergic contact dermatitis or develop tolerance. This review offers a general overview of human biomonitoring, including information about its typical application and methodology. Furthermore, studies that have attempted to perform simultaneous biomonitoring and patch testing are reviewed. It is concluded that all studies conducted until the present have focused on one or two routes of exposure (typically skin and oral exposure, but also skin and airway exposure), whereas no studies have investigated all routes at the same time. Also, there is a need for prospective studies, as all epidemiological studies so far have been cross-sectional.

Origin of exhaled breath particles from healthy and human rhinovirus-infected subjects

BACKGROUND

Exhaled breath studies suggest that humans exhale fine particles during tidal breathing, but little is known of their physical origin in the respiratory system during health or disease.

METHODS

Particles generated by 3 healthy and 16 human rhinovirus (HRV)-infected subjects were counted using an optical particle counter with nominal diameter-size bins ranging between 0.3 and 10 μm. Data were collected from HRV-infected subjects during tidal breathing. In addition, data from healthy subjects were collected during coughs, swallows, tidal breathing, and breathing to total lung capacity (TLC) and residual volume (RV). Using general additive models, we graphed exhaled particle concentration versus airflow during exhalation. Exhaled particles were collected from expired air on gelatin filters and analyzed for HRV via quantitative PCR.

RESULTS

HRV-infected subjects exhaled from 0.1 to 7200 particles per liter of exhaled air during tidal breathing (geometric mean = 32 part/L). A small fraction (24%) of subjects exhaled most (81%) of the particles measured and 82% of particles detected were 0.300-0.499 μm. Minute ventilation, maximum airflow during exhalation, and forced expiratory volume 1 second (FEV(1) % predicted) were positively correlated with particle production. No human rhinovirus was detected in exhaled breath samples. Three healthy subjects exhaled less than 100 particles per liter of exhaled air during tidal breathing and increased particle concentrations more with exhalation to RV than with coughing, swallowing, or rapid exhalation.

CONCLUSIONS

Submicron particles were detected in the exhaled breath of healthy and HRV-infected subjects. Particle concentrations were correlated with airflow during the first half of exhalation, and peaked at the end of exhalation, indicating both lower and upper airways as particle sources. The effect of breathing maneuver suggested a major contribution from lower airways, probably the result of opening collapsed small airways and alveoli.

Increased metal concentrations in exhaled breath condensate of industrial welders

It was the aim of this study to evaluate the effect of different devices on the metal concentration in exhaled breath condensate (EBC) and to prove whether working conditions in different welding companies result in diverse composition of metallic elements. The influence of two collection devices (ECoScreen, ECoScreen2) on detection of metallic elements in EBC was evaluated in 24 control subjects. Properties of ECoScreen and a frequent use can alter EBC metal content due to contamination from metallic components. ECoScreen2 turned out to be favourable for metal assessment. Concentrations of iron, nickel and chromium in EBC sampled with ECoScreen2 were compared between non-exposed controls and industrial welders. Metal concentrations in EBC were higher in 36 welders recruited from three companies. Exposure to welding fumes could be demonstrated predominantly for increased iron concentrations. Concentrations of iron and nickel differed by working conditions, but chromium could not be detected in EBC.

Use of exhaled breath condensate to investigate occupational lung diseases

PURPOSE OF REVIEW

The present study reviews recent data concerning the assessment of exhaled breath condensate (EBC) pulmonary biomarkers in the field of occupational medicine.

RECENT FINDINGS

EBC is a suitable matrix to assess respiratory health status in workers exposed to pneumotoxic substances, due to its ability to quantify lung tissue dose and consequent pulmonary effects. Published data show that toxic metals and trace elements are detectable in EBC, raising the possibility of using this medium to quantify the lung tissue dose of metals occurring in occupational settings. EBC analysis of biomarkers of exposure highlighted the potential use of EBC as completion of the biological monitoring of pneumotoxic compounds. Different biomarkers of effect, such as oxidative stress and inflammatory-derived biomarkers have been applied in the investigation of occupational asthma and pneumoconiosis, suggesting that the collection of EBC may contribute to studying the pathological state of the airways of workers with acute and chronic exposure to pollutants. EBC measurements also seem to be reliable to detect the presence of carcinogenic processes in the respiratory system, by the analysis of various markers of oxidative stress, angiogenesis and DNA alterations related to lung cancer. This approach may open new frontiers in the study of workers currently or previously exposed to pulmonary carcinogenic agents.

SUMMARY

The analysis of EBC is one of the most promising methods currently available for the study of pulmonary biomarkers of exposure, effect and susceptibility in occupational settings; being collected in a totally noninvasive way, it is particularly suitable to be applied in field studies and for longitudinal assessments of pulmonary biology.

Biological effect markers in exhaled breath condensate and biomonitoring in welders: impact of smoking and protection equipment

PURPOSE

The objective of this study was to investigate the effect of welding as well as the impact of smoking and protection measures on biological effect markers in exhaled breath condensate. Additionally, biomonitoring of chromium, aluminium and nickel in urine was performed to quantify internal exposure.

METHODS

Exhaled breath condensate (EBC) and urine samples of 45 male welders and 24 male non-exposed control subjects were collected on Friday pre-shift and after 8 h of work post-shift. In EBC, biological effect markers such as malondialdehyde, nitrite, nitrate, 3-nitrotyrosine, tyrosine, hydroxyproline, proline, H(2)O(2) and pH-value were measured while aluminium, nickel, and chromium were measured in the urine samples.

RESULTS

Although internal exposure to aluminium, nickel and chromium in this study was low, welders showed significantly increased concentrations of all these parameters at baseline compared to non-exposed controls. Moreover, welders had higher nitrate concentrations in EBC at baseline and after shift. Nitrate concentration was considerably lower after shift if personal protection equipment was used. H(2)O(2) was increased only when subjects smoked during shift.

CONCLUSION

It has been shown that welding-associated long-term and short-term health effects could be detected in a population of welders. The results also showed that using personal protection equipment is of high importance and H(2)O(2) may be an effect marker associated with smoking rather than with welding fumes, while nitrate in EBC seems to be sensitive to welding fume exposure.